Question

multiple choice
identify the choice that best completes the statement or answers the question. clearly write your choice on the line next to
the question. (3pts each 51 points total)

1. which compound below is ionic?

a. bacl₂
d. so₃
b. h₂s
e. c₁₂h₂₂o₁₁
c. cf₄

1. in vsepr theory, molecular geometry is determined by

a. electron-electron attractive forces.
d. proton-proton repulsive forces.
b. electron-proton attractive forces.
e. electron-nucleus attractive forces.
c. electron-electron repulsive forces.

1. what is the charge on the manganese ion in mns₂?

a. -1
d. +1
b. -2
e. +2
c. +4

1. which diagram below shows the orientation of the net dipole for ocs?

a. o = c = s
d. o = c = s
b. o = c = s
e. none of these
c. o = c = s

1. which bond below is least polar?

a. h—f
d. h—cl
b. h—b
e. h—o
c. h—n

1. a covalent bond results when

a. atoms pool their electrons to form a \sea\ of electrons.
b. atoms have outer electrons with the same principal quantum number.
c. an atom has eight valence electrons.
d. electrons are transferred from one atom to another atom.
e. electrons are shared between a pair of atoms.

Explanation:

1. Ionic compounds are formed between metals and non - metals. Barium (\(Ba\)) is a metal and chlorine (\(Cl\)) is a non - metal in \(BaCl_{2}\). The other compounds (\(H_{2}S\), \(CF_{4}\), \(SO_{3}\), \(C_{12}H_{22}O_{11}\)) are covalent (formed between non - metals).
2. In VSEPR (Valence Shell Electron Pair Repulsion) theory, molecular geometry is determined by electron - electron repulsive forces. Electron pairs (bonding and non - bonding) repel each other to get as far apart as possible.
3. In \(MnS_{2}\), sulfur (\(S\)) has an oxidation state of \(- 2\). Let the charge on manganese (\(Mn\)) be \(x\). Using the formula \(x+2\times(-2)=0\) (since the compound is neutral), we get \(x - 4=0\), so \(x = + 4\).
4. The electronegativity order is \(O>C>S\). The dipole moment direction is from the less electronegative atom to the more electronegative atom. So the net dipole is from \(C\) to \(O\) (since \(O\) is more electronegative than \(S\)).
5. The polarity of a bond is determined by the electronegativity difference (\(\Delta EN\)). The electronegativity values: \(EN_{H}=2.1\), \(EN_{F}=4.0\), \(\Delta EN_{H - F}=4.0 - 2.1 = 1.9\); \(EN_{B}=2.0\), \(\Delta EN_{H - B}=2.1-2.0 = 0.1\); \(EN_{N}=3.0\), \(\Delta EN_{H - N}=3.0 - 2.1=0.9\); \(EN_{Cl}=3.0\), \(\Delta EN_{H - Cl}=3.0 - 2.1 = 0.9\); \(EN_{O}=3.5\), \(\Delta EN_{H - O}=3.5 - 2.1=1.4\). The smallest \(\Delta EN\) is for \(H - B\).
6. A covalent bond is formed when electrons are shared between a pair of atoms. Option (a) is for metallic bonding, (d) is for ionic bonding.

Answer:

1. a. \(BaCl_{2}\)
2. c. electron - electron repulsive forces
3. c. \(+4\)
4. a. (the diagram with the arrow from \(C\) to \(O\))
5. b. \(H - B\)
6. e. electrons are shared between a pair of atoms